Work-clamp-spreading mechanism for sewing machines



A. F. CARLSON ET AL Aug. 27, 1929.

WORK CLAMP SPREADING MECHANISM FOR SEWING MACHINES Filed July 26 1926 4 Sheets-Sheet lnvenToTS. Axe! F Carlson He-rbefT ElAHhens b wwkw Aug. 27, 1929. A. F. CARLSON ETAL 1,726,333 WORK CLAMP SPREADING MECHANISM FOR SEWING MACHiNES Filed July 26, 1926 4'Sheets-Sheet 2 Fig.2 1

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Aug. 27, 1929. I A. F. CARLSON ETAL 1,726,383

WORK CLAMP SPREADING MECHANISM FOR SEWING MACHINES Filed July 26, 1926 4 Sheets-Sheet 4 7| \nvenrors. I5 54 27 Axel Fcorlson Herberf E.A\Then's- Afiys.

Patented Aug. 27, 1929 UNITED STATES PATENT I OFFICE.

AXEL F. CARLSON, OF CAMBRIDC-rE, AND HERBERT E. ALTHENS, F AUBURNDALE, MASSACHUSETTS, ASSIGNORS TO THE REECE BUTTON HOLE MACHINE COMPANY, 033 BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

WORK-CLAMP-SLPREADING MECHANISM FOR SEWING MACHINES.

Application filed. July 26, 1926. Serial No. 124,922

This invention relates to buttonhole sewing machines and particularly to the-work clamp. It has forits object to provide a novel means for spreading the clamp after it has closed on the work in order to place the cloth under slight tension while the buttonhole is being sewed.

In order to give an understanding of the invention we have illustrated in the drawings a selected embodiment thereof which will now be described after which the novel features will be pointed out in the appended claims.

Fig. 1 is a side View of a portion of a sewing machine having the invention applied thereto;

Fig. 2 is a top plan view of the work clamps;

3 is a section on the line 33, Fig. 1;

Fig. 4 is a section on the line 4- 1, Fig. 2;

Fig. is a section on the line. 5-5, Fig. 2; F. a section on the line 6-6, Fig.

ig. 7 is a detail view similar to Fig. 4 showing the position of the arm and rocking member 27 when the clamps are raised;

8 is a fragmentary view showing the operation of the latch for raising the clamps;

Fig. 9 is a fragmentary view showing the position of the toggle device when the clamps are opened;

The present invention is shown as embodied in sewing machine similar to that ill stratecl in co-pending applications Serial .9523, filed January 6th, 1926, and Serial ilo. 112,507, filed May 29th, 1926, both filed by Axel F. Carlson.

The. sewing machine herein illustrated has the frame 1 on which is supported the usual overhanging arm 2 in which is mounted a ver ically-reciprocating needle bar 3 carrying the upper needle 1. The frame is also provided with a work-supporting arm 5 on which the work is supported.

The operating mechanism is driven from a driving shaft 6 which in turn is rotated from a constantly-rotating driving pulley 7, the latter being driven by the driving belt 8. A suitable clutch mechanism (not shown) is provided for connecting the pulley 7 to the drivingshaft 6 and for disconnecting it therefrom. This clutch. may have any suitable construction such for instance as that illustrated in the above-mentioned co-pending applications but as the present invention CE {It ually-controlled device. The actuator 10 is movable vertically and is provided with a head 11 through which the pull rod 9 extends, said rod having a collar 12 thereon which is engaged by the head as the actuator is moved downwardly thereby pulling the rod 9 down and throwing the clutch into engagement.

The work is held during the stitching operation by a suitable Work holder comprising a clamp plate or work support 13 on which the work rests and two spring-pressed work clamps 14: which engage the upper side of the work and clamp it against the plate 13 all as usual in buttonhole sewing machines.

The work clamps 14 are carried by clamp arms 15 which are pivoted at their rear ends as shown at 16 to a rocking support 17, the latter being pivotally mounted on the clamp plate 13 as shown at 18 thereby to provide for up and down swinging movement of the clamp arms 15. .The clamp arms are acted on by springs 19 which yieldingly hold the clamps against the work. These springs are shown as encircling pins 20, the lower ends of which bear against the clamp arms 15 and the upper ends of which extend through openings in a bracket arm 21 that is secured to and rises from the clamp plate. The springs are confined between the bracket arm and collars 22, which are adjustably mounted on the pins. Said springs, therefore, have a tendency to depress the clamp arms.

The clamps are raised or opened and held in their raised position by means similar to that illustrated in the above-mentioned coaendin ap lications.

mounted. at 28 in ears 29 formed on the under side of the rocking support 17 This rocking member 27 is thus capable of rocking about its axis 28 relative to the support 17.

The end 26 of the arm 25 and the rocking member 27 are connected together, this being herein accomplished by means of a loop 80 which is pivoted to the end 26 of the arm 25 and into which the end of the arm 27 extends. This loop has a flexible connection 81 connected thereto which leads over suitable guides 82 and extends downwardly to a treadle or other manually-controlled device. The flexible connection 81 thus provides means by which the clamps can be raised manually at any time desired.

The rocking member 27 has a rear extension 30 in which is adjustably mounted an upstanding arm 31 which extends through an opening 32 on the rocking support 17 and the upper end of which is provided with ahead 33.

The parts are shown in 4 in the position they occupy when the clamps are closed onto the work. when the clamps are to be raised the rock shaft 24 is turned thereby swinging the arm 25 upwardly into the position shown in Fig. 7, thereby bringing the head 33 against the upper side of the rocking support 17. This limits the swinging movement which the rocking member 27 can have relative to the support 17 and further upward movement of the arm 25 into the dotted line position Fig. 7 will operate through the member 27 to raise the clamps.

The clamps are raised at the end of the sewing operation and are held raised by a latch 34 which engages a projection 85 extending from a crank arm 36 that is rigid with the outer end of the rock Shaft 24. At the completion of the sewing operation the latch, which during the sewing operation is in the full. line position Fig. 8 is moved forwardly into the dotted line position so as to hook over the projection 35 and said latch is then moved backwardly to its full line position again thereby swinging the arm 36 v ently described.

When the machine is started the latch 34 is raised thereby releasing it from the arm 25 and allowing the springs 19 to depress the work clamps onto the work. This release of the latch is accomplished by means similar to that shown in co-pending application Serial No. 112,507. Pivoted to the bed frame is a swinging arm 37 carrying a pin 88 adapted to engage a cam surface 39 on the under side of the latch 84. This swinging arm is connected by a link 40 to an elbow lever 41 pivoted to the frame at 42. This elbow lever has a link or connection 43 depending therefrom which extends through the head 11 and is provided with a collar 44 adapted to engage the under side of the head. When, therefore, the connection 10 is depressed to start the machine the downward movement of the head 11 will operate through the connections above described to swing the lever 37 and cause the pin 38 to engage the cam surface 39. This will raise the latch as shown by dotted lines Fig. 1 thereby disengaging it from the projection 35 and permitting the clamps to close.

The arrangement for actuating the clamps is such that the clamps will be released and closed before the clutch is thrown and for this purpose the collar 44 is so adjusted relative to the collar 12 that when the head 11 moves downwardly it will first engage the collar 44 thereby to release the latch and will then engage the collar 12 thereby to throw the clutch. After the clamps 14 have been moved into clamping engagement with the work they are automatically spread slightly so as to place the work under tension and the present invention relates particularly to the mechanism for thus spreading the clamps. The clamp arms are connected by a toggle joint device 45 comprising the two toggle links 46 pivotally connected together by the pivot pin 47 and having a pivotal connection with the arms 15 at 48.

lVhen the clamps are opened this toggle lever device is slightly buckled or bent as shown in F ig. 9 and after the clamps have closed onto the work then the toggle is straightened into the position shown in Fig. 2 thereby forcing the clamp arms 15 apart and spreading the clamps. This movement of the toggle is accomplished by the movement'of the rocking member 27 and arm 26 from. the position shown in Fig. 7 to that shown in Fig. 4 and such movement is derived from the swinging movement of the lever 37 which is above referred to. This lever 37 has an arm 49 rigid therewith provided at its end with a cam surface 50 that is adapted to engage a roll 51 carried by the projection 35. When the actuator 10 is operated the first or initial downward move ment of the head 11 will swing the lever 37 as above described thereby releasing the latch 34 and permitting the clamps to close. Continued downward movement of the head will give the arm 37 a further swinging movement thereby bringing the cam surface 50 against the roll 51 and positively rocking the shaft 24 from the position shown in Fig. 7 to that shown in Fig. 4. This turning of the rock shaft 24 from the position shown in Fig. 7 to that shown in Fig. 4 operates to actuate the toggle device from the position shown in Fig. 9 to that shown in Fig. 2 thereby spreading the clamps.

The rocking member 27 is provided with an tip-standing tooth 52 which engages in a recess 53 formed in the under side of the gooseneck portion 54 of a slide 55, the latter sliding on the upper surface of the rocking member 17 between the guides 56. The pivot pin 47 of the toggle lever device is elongated and extends into an aperture formed in the slide 55 and thus sliding movement of the slide 55 will operate to straighten and break the toggle lever thus spreading the clamps and moving them together. When, therefore, the member 10 is operated the latch 34 will first be released. thus allowing the clamps to close onto the work and immediately thereafter the cam 50 will operate against the roll 51 thereby turning the rocking member 27 and moving the slide 55 which will straighten the toggle and spread,

the clamps thus placing the work under tension.

When the sewing operation has been completed and the latch 34 is moved to raise the clamps the first or initial backward swinging movement of the arm 36 will turn the member 27 from the position shown in Fig. 4 to that shown in Fig. 7 thereby moving the slide 55 backwardly and buckling the toggle device. This will cause the clamps to move toward each other. l/Vhen the rocking member 27 has been brought into the position shown in Fig. 7 then further rearward movement of the latch will operate through the rock shaft 24 and arm 25 to raise the clamps from the work against the action of the springs 19 and during this movement the rocking member 27 moves as a unit with the rocking member 17.

The latch 3a is operated in the same mannor as is illustrated in the above-mentioned applications. It is pivotally connected to an arm 57 that is fast on a rock shaft 60, said rock sha ft having another arm 61 there on which is adaptedto be acted on by a cam 62 mounted on a shaft 63. This shaft 63 is given one rotation at the time that the pulley 7 is disengaged from the shaft and the machine is brought to rest, the movement of the shaft 63 being initiated by the stop motion, all as shown and described in the abovementioned applications.

The cam 62 is normally in the position shown in Fig. 1 in which position it holds the latch retracted but when the machine has been brought to rest the shaft 63 is given one rotation and as the cam 62 rotates the latch 34; will first be moved forwardly, under the influence of the spring 65, into the dotted line position Fig. 8 as the arm 61 runs down the cam 62 and then said cam will act on the arm to cause the latch to move rearwardly thereby to raise the clamps as above described.

l/Ve have herein illustrated an adjustable connection between the toggle lever device justing the clamps toward and from each other for different sizes of buttonholes. Each arm 15 has a plate 70 pivotally connected, thereto at 71, each plate being clamped to the arm 15 by means of a clamping screw 72 which extends through a slot 73 in the end of the plate and screws into the arm 15. The toggle arms 46 are pivotally connected. to the plates 70 through the pivotal connection 48. When the device is in operation the two plates 7 O are rigidly clamped to the clamp arms 15 so that the same effect is produced as if the toggle levers were pivoted to the arms 15. This construction, however, provides for an adjustment of the clamp arms relative to each other without disturbing the toggle device 45.

By loosening the screws 72 the arms 15 may be separated or closed together so as to provide the desired initial adjustment of the work clamps relative to each other. During this adjustment the pivotal connections 18 remainsstationar-y and as the clamp arms are adjusted toward and from each other the plates 70 will be swung about their pivots 71. When the clamps have been given the desired initial adjustment relative to each other the clamp screws 72 are tightened thus rigidly clamping the plates 70 again to the clamp arms 15.

The toggle device 45, and its actuating mechanism is so constructed that when the clamps are closed and have been spread as shown in Fig. 2 the center 47 of the toggle device is carried slightly bythe center line of the pivot pins 4-8. This results in locking the toggle in its straightened position be cause the tension on the cloth tends to swing the clamp arms 15 toward each other and since the toggle has been carried slightly by the center this tendency will prevent it from becoming accidentally buckled.

While we have herein illustrated a selected embodiment of the invention we do not wish to be limited to the constructional features shown.

We claim:

1. In a buttonhole sewing machine, the combination with a work support, of a rocking support, two clamp. arms pivoted there to toswing toward and from each other, a work clamp carried by each arm, a toggle lever device connecting said arms, a spring for closing the clamps onto the work, and

means operative after the clamps have closed onto the Work to actuate the toggle thereby to spread the clamps. I

'2. In a buttonhole sewing machine, the combination with a work support, of a rocking support, two clamp arms pivoted thereto to swing toward and from each other, a work clamp carried by each arm, a toggle lever device adjustably connected to both arms, a spring for closing the clamps onto the work, and means operative after the clamps have closed onto the work to actuate the toggle thereby to spread the clamps.

3. In a buttonhole sewing machine, the combination with a work support, of two work clamps, clamp arms by which said work clamps are supported, said arms being movable toward and from each other, a plate adjustably secured to each clamp arm, a toggle lever device connecting said plates, means for closing the clamps onto the work, and means operative after the clamps are closed to actuate the toggle device to spread the clamps.

4. In a buttonhole sewing machine, the combination with a work support, of two work clamps, clamp arms by which said Work clamps are supported, said arms being movable toward and from each other, a plate pivoted to each clamp arm, means to clamp each plate to its clamp arm in adjusted position, a toggle. device connecting said plates, means to close the clamps onto the work, and means operative after the clamps are closed to actuate the toggle to spread the clamps.

5. In a buttonhole sewing machine, the combination with a work support, oi two work clamps, a rocking support, clamp arms pivoted thereto and by which said work clamps are supported, said arms being swingable toward and from each other, a toggle device connecting said arms, a rocking member capable of rocking movement relative to said clamp arms, means to close the clamps onto the work, means to actuate the rocking member after the clamps are closed, and means actuated by the rocking member to operate the toggle device thereby to spread the clamps.

6. In a buttonhole sewing machine, the combination with a work support, of two work clamps, a clamp arm by which each work clamp is supported, said clamp arms being movable toward and from each other, a toggle lever device connecting said clamp arms, a spring for holding the clamp yieldingly against the work, a latch to hold the clamps'raised'when themachine is at rest, a movable-actuating member, and means rendered operative during the initial movement of said actuating member to release the latch and during further movement toactuate the toggle device to spread the clamps.

7. In a buttonhole; sewing machine, the

combination with a work support, of two work clamps, cleamp arms by which the work clamps are supported, said clamp arms being movable toward and from each other, a toggle lever device connecting said arms, a spring for closing the clamps onto the work, means operative after the clamps have closed onto the work to actuate the toggle thereby to spread the clamps, and means to adjust each clamp arm relative to the other without disturbing the toggle lever device.

8. In a buttonhole sewing machine, the

, combination with a work support, of a rocking clamp carrier, clamp arms pivotally secured thereto, work clamps carried by the clamp arms, a toggle device connecting the clamp arms, a rocking member carried by the clamp carrier, means to close the clamps onto the work, means to rock said member after the clamps are closed, and means actuated by the rocking member to actuate the toggle device thereby to spread the clamps.

9. In a buttonhole sewing machine, the

combination with a rocking support, of two clamp arms pivoted thereto to swing about axes at right angles to the plane of the work, work clamps carried by said arms, a toggle lever device connecting said arms, a spring tor'closing the clamps onto the work, and means operative after the clamps have closed onto the work to actuate the toggle lever device thereby to spread the clamps.

10. In a buttonhole sewing machine, the combination with a work support, of a rock ing support pivoted to the work support to turn about a horizontal aXis, two clamp arms pivoted to the rocking support to turn about vertical axes, a work clamp carried by each arm, a spring for closing the work clamps onto the work, a toggle device connecting the clamp arms, and means operative after the clamps have closed onto the work to actuate the toggle and thereby spread the clamps.

In testimony whereof, we have signed our names to this specification.

AXEL F. OARLSON. HERBERT E. ALTHENS. 

